Solubility of Methane in Water:  The Significance of the Methane−Water Interaction Potential

Abstract

The influence of the methane-water interaction potential on the value of the Henry constant obtained from molecular dynamics simulations was investigated. The SPC, SPC/E, MSPC/E, and TIP3P potentials were used to describe water and the OPLS-UA and TraPPE potentials for methane. Nonbonding interactions between unlike atoms were calculated both with one of four mixing rules and with our new methane-water interaction potential. The Henry constants obtained from simulations using any of the mixing rules differed significantly from the experimental ones. Good agreement between simulation and experiment was achieved with the new potential over the whole temperature range.

Isolating the non-polar contributions to the intermolecular potential for water-alkane interactions

“…With water energy of 220 K, the water-methane interaction energy is ε MW /k = 180.5 K which means a correction to the Berthelot rule of 1.65 when using the SPC/E model for water and the TraPPE model for methane. The correction here is much higher than what was suggested previously by studies of methane solubility in water 14,33 with one exception. The proposed value is only 7% higher than the interaction energy proposed by Pratt and Chandler.…”

Molecular dynamics simulation of the CH4 and CH4–H2O systems up to 10GPa and 2573K

“…Duan and Zhang (2006) successfully validated the MLCS technique by reproducing thousands of experimental data points for the H 2 O-CO 2 system, and extended the experimental database from less than 1000 K and 1 GPa to 2573 K and 10 GPa. The predictability of MLCS has also been demonstrated by many prior workers (Chen et al, 1998;Errington et al, 1998;Birkett and Do, 2004;Konrad and Lankau, 2005;Zhang and Duan, 2005). The success of MLCS, to a large extent, relies on the development of accurate potential models, which can be evaluated from experimental data or from quantum mechanics methods (ab initio etc.).…”

Molecular dynamics simulations of the diffusion coefficients of light n-alkanes in water over a wide range of temperature and pressure

“…Despite the significant effort that was put into the prediction of phase equilibria of mixtures of H 2 O with n-alkanes [36][37][38][39][40][41][42][43][44] by many research groups, only one molecular simulation study exists in the literature for the diffusion coefficient of CH 4 in H 2 O, while none for higher n-alkanes. Specifically, Shvab and Sadus [45] have performed an extensive series of molecular dynamics (MD) simulations for the calculation of a number of thermodynamic properties and diffusion coefficients of the H 2 O-CH 4 mixture for various CH 4 compositions.…”